This invention pertains to a valve having separate closures for an inlet and an outlet respectively. The valve has particular utility in food-handling systems and other systems wherein fluent materials may contain particulate matter.
In food-handling systems, as an example, particulate matter may block internal apertures and thus prevent complete closure of ball valves, gate valves, butterfly valves, spool valves, and other single-closure valves. Because of resultant leakage, such valves have limited utility as control valves for volumetric filling and similar applications.
Repeated cycling often is used, as an expedient to clear such incompletely closed valves, particularly when aseptic conditions and other conditions of continuous operation do not allow the valves to be opened for manual removal of blockage. Subjected thereby to rough handling, meat chunks, vegetable pieces, macaroni bits, and other types of delicate particulates tend to be masticated and otherwise physically damaged beyond tolerable limits.
A need thus has existed for a new and improved valve for fluent materials, which may contain particulate matter, as discussed above. This invention is addressed to such need.